1. Field of the Invention
This invention generally relates to a conveyor system adapted to cause a cylindrical belt having materials to be conveyed, such as granular or powdered materials carried therein and completely sealed in a condition of being suspended from wire ropes, to travel in a circulating fashion.
2. Description of the Prior Art
Belt conveyor systems used to convey materials by way of a flat belt traveling on carrier rollers are well known. Such flat belt-type conveyors, however, possess several disadvantages, the most notable of which is the unavoidable dispersion of the materials to be transported when granular materials or the like are transported, and in addition thereto, the unsuitableness in the case of long distance transportation, or in the case of an inclined transportation. In order to overcome the various disadvantages noted above with respect to flat belt conveyors, cylindrical belt conveyors have been developed. In the cylindrical belt conveyor, wire ropes are mounted along the traveling passage of the belt to suspend the belt therefrom, and the belt is caused to travel in circulating fashion at a predetermined speed. In this case, the conveyor belt is cylindrically held, and materials to be transported are transported while being carried within the cylindrical belt. With this arrangement, the materials to be transported were completely prevented from being dispersed during a period of transportation, and further belt-transportation of the material for a long distance was made possible, even if the site involved ups and downs, or were inclined, by the mere provision of wire ropes mounted in a manner similar to that of a ski lift in the Gelande or a slope.
To achieve reliable and more effective operation and to achieve operation with a minimum of damage to the belt, it is extremely important for the rope-suspension type cylindrical belt conveyor to move both the rope and the belt in a well balanced condition to minimize rocking of the belt for maintaining safety of a high degree and to ensure the operation of engaging and disengaging the belt as required when a belt gripper, which is used to suspend the belt from the rope, is engaged with or disengaged from the belt before and behind the loading station or unloading station of the materials to be transported.
Where the arrangement is made in a traveling belt so that only a suspending rope is driven to let the belt follow the travel of the rope, the full load of the horizontal or forward movement of load and the belt-supporting vertical load is dynamically loaded upon the rope. For this reason, a greater rope driving force becomes necessary and the degree of fatigue of the rope will increase, to thereby cut the service life of the rope, and in addition, there is a tendency showing a delayed response of the follower belt in starting, traveling and stopping of the rope. Further, the traveling inertia becomes extremely unbalanced, particularly due to the difference in load between the loaded side where materials to be transported are loaded and the return side where no load is carried, and the difference in load, even on the loaded side, due to the one-sided placement of materials to be transported on the belt, and as a result, the response of the belt to the rope is greatly delayed and partly differs, to unavoidably produce rocking and strain of the belt, resulting in disengagement or displacement of the belt gripper from the belt, and in the limitation of the belt traveling speed.